# 1
# n=int(input('请输入一个整数:'))
# sum=0
# for i in range(n+1):
#     sum+=i
# print('1-%d的求和结果为%d'%(n,sum))
# 2
# l=[]
# for i in range(3):
#     x=int(input('请输入三个整数:'))
#     l.append(x)
# l.sort()
# print(l)
# 3
# for i in range(1,10):
#     for j in range(1,i+1):
#         print("%d*%d=%d"%(j,i,i*j),end=' ')
#     print('')
# 4
# l=[1,2]
# n=int(input("斐波那契数列长度:"))
# while (len(l)<n):
#     l.append(l[len(l)-1]+l[len(1)-2])
# print(l)
# 5
# for i in range(2,1001):
#     s=0
#     for j in range(1,i):
#         if i%j==0:
#             s+=j
#     if s==i:
#         print("It's a perfect number:{}".format(i))


